Identifying gaps on health impacts, exposures, and vulnerabilities to climate change on human health and wellbeing in South America: a scoping review

Summary There is an important gap in regional information on climate change and health, limiting the development of science-based climate policies in South American countries. This study aims to identify the main gaps in the existing scientific literature on the impacts, exposure, and vulnerabilities of climate change on population health. A scoping review was performed guided by four sub-questions focused on the impacts of climate change on physical and mental health, exposure and vulnerability factors of population to climate hazards. The main findings showed that physical impacts mainly included infectious diseases, while mental health impacts included trauma, depression, and anxiety. Evidence on population exposure to climate hazards is limited, and social determinants of health and individual factors were identified as vulnerability factors. Overall, evidence on the intersection between climate change and health is limited in South America and has been generated in silos, with limited transdisciplinary research. More formal and systematic information should be generated to inform public policy. Funding None.


Introduction
Anthropogenic climate change, understood as "a change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer" and due to "persistent anthropogenic changes in the composition of the atmosphere or in land use", 1 is threatening the health and wellbeing of South American populations by increasing the risk of climate-sensitive temperature-, flood-, and drought-related morbidity and mortality; fresh water and food insecurity; and infectious diseases, especially those related to mosquito transmission. 1,2][4][5] Despite the growing global evidence on climate hazards and their impacts on human health and wellbeing, global estimates often hide significant differences at regional and local levels.For example, high temperatures and more extreme weather events might be present in different cities worldwide; however, the impact on human populations is mediated by social vulnerability factors or individual susceptibilities, including poorly planned urban and peri-urban features, high prevalence of pre-existing comorbidities, and marginalised groups including indigenous populations, which tend to increase the risk of negative health outcomes within populations. 6,7Therefore, to understand the magnitude of climate change impacts on population health and identify the most affected populations, more detailed and countryspecific analyses are needed to adequately inform the public, policymakers, the media, and key stakeholders. 8nfortunately, regional and sub-regional information on the relationship between climate change and population health has been mainly generated in high-income countries, including Australia, Canada, those in Europe, and the United States of America. 9This situation creates significant knowledge gaps in low and middle-income countries, including those from South America (SA).Additionally, existing evidence mainly focuses on specific countries, lacking a broader and systemic perspective of the situation in the region. 9This lack of evidence and insights might affect and limit the decision-making capacity and impair climate adaptation and mitigation policies.To address this issue, the Lancet Countdown South America (LCSA) aims to review and discuss the current regional evidence regarding health and climate change across five key domains (i) health hazards, exposures, and impacts; (ii) adaptation, planning, and resilience for health; (iii) mitigation actions and health cobenefits; (iv) economics and finance; and (v) public and political engagement.
This scoping review aims to identify the main gaps in the existing scientific literature on the impacts of anthropogenic climate change on human health and wellbeing in South American populations, the degree of human populations exposure to climate change hazards, and the main vulnerability and/or susceptibility factors to climate hazards that could increase the risk of climate change adverse impacts on health and wellbeing.This information will be useful to inform future research and policy aimed at promoting adaptation and resilience to climate change, as well as preventing and ameliorating the projected climate-related health impacts.

Design and search strategies
This scoping review (ScR) followed the Arksey and O'Malley framework. 10The overarching research question was "What is the scientific evidence on the impacts, exposure, and vulnerabilities to climate change hazards on human health and wellbeing in South America?"From this question, four specific sub-questions were proposed to simplify the searches and to focus the identification of more specific knowledge gaps: -RsQ1: What are the main impacts of climate change hazards on physical health and wellbeing in South America?-RsQ2: What are the main impacts of climate change hazards on mental health and wellbeing in South America?-RsQ3: To what extent human populations in South America are exposed to the hazards of climate change.-RsQ4: What are the main vulnerabilities or susceptibility factors present in the South American human population groups that could increase the risk of climate change adverse impacts on health and wellbeing?
Different search strategies were defined for each research question (Supplementary Tables S1-S4 in the Supplementary Material).The understanding of the concepts involved in each research sub-question is based on the definitions of the Lancet Countdown global reports. 11-14Searches were conducted using keywords and synonyms in English.
Given that the purpose was to retrieve scientific evidence relevant to South America, the following databases were considered: Web of Science, PubMed, PubMed (MeSH), ProQuest, Scopus, SciELO, and BIREME/LILACS.All these databases complement each other to deliver information from multidisciplinary, biomedical, and regional databases.
The searches were performed between October and November 2021.The identified references in every database were downloaded and then uploaded to Rayyan® online manager.All duplicates were removed, and the final references were analysed.This review did not need ethical approval as it worked with publicly available, secondary data.

Selection of studies
The selection of studies was independently done by two reviewers (LR, MGC, or WM) following two main steps.First, titles and abstracts were analysed looking for articles that could provide relevant information to answer the research questions.Second, from the selected titles and abstracts, full texts were searched and analysed looking for articles that provided information on i) impacts of climate change on human health and wellbeing, ii) the degree of exposure to climate hazards, or iii) the main vulnerability factors that increase the risk of negative impacts from climate change.The selection of articles was restricted to South American countries only.Any disagreements between the reviewers were resolved by a third reviewer (YKPS, AGL, EF, or YA) who analysed the records and made a final decision.
Studies were included if they were published in Spanish, English, or Portuguese, and included information on the impacts, exposure, and vulnerabilities of climate change on population health in South America.There were no restrictions for publication dates.Studies were excluded if they were focused on non-human animals; opinion articles; or did not analyse the link between climate change impacts, exposures, or vulnerabilities and population health.

Data extraction process
Two reviewers (LR, MGC, or WM) independently extracted all relevant information from full texts using a standardised form.This form collected the following information: title of the article; year of publication; authors; type of publication; a brief context of the study; the aim of the article; country and/or region of study; main characteristics of the methodology; and main findings.A group of third reviewers (YKPS, AGL, EF, and YA) evaluated the consistency of data extraction and checked any necessary re-revision of information from the extracted articles.

Critical appraisal
Critical appraisal was performed to complement and understand the general quality of the evidence retrieved, and therefore, complement its mapping.Due to the variety of designs, the Joanna Briggs Institute guidelines were used (https://jbi.global/critical-appraisal-tools).

Synthesis of results
The overall characteristics of the studies, including country and type of publication were analysed separately for each sub-question.Findings about the impacts on physical and mental health were summarised by themes.For exposure, the findings were grouped according to exposure factors, geographic areas and group of people exposed.For vulnerabilities, information was also synthesised by groups of vulnerability or susceptibility factors, identifying the main individual or social factors that increase health vulnerability to climate hazards.
The presentation of this ScR follows the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). 15

Results
A total of 713, 828, 1116, and 931 studies were obtained from all databases combined for physical impacts, mental health impacts, exposures, and vulnerabilities, respectively.Supplementary Tables S1-S4 in the Supplementary Material show the number of references retrieved by each database.
After duplicate removal, eligible studies reduced to 550, 721, 781, and 697 for physical impacts, mental health impacts, exposures, and vulnerabilities, respectively.Fig. 1 shows the studies that were retrieved, screened, selected to be fully analysed, and selected to be included in this ScR.
After screening the title and abstracts as well as full texts, a total of 47 studies were included for physical impacts, 12 for mental health impacts, 21 for exposures, and 30 for vulnerabilities.A detailed analysis of the articles is provided in the following sections.
The 37 original studies were scattered among multiple topics, including mortality (n = 6), 22,26,27,34,52,64 dengue fever (n = 5), 33,44,46,55,58 leishmaniasis (n = 5), 20,35,45,48,65 diarrheal disease (n = 4), 31,40,41,62 malaria (n = 3), 43,47,51 and respiratory diseases (n = 3). 17,18,25The main study covariates were primarily climate-related (n = 23) and El Niño-Southern Oscillation (ENSO) (n = 12), 35,[38][39][40]43,[45][46][47][48]55,58,65 but also extreme weather events, including extreme temperatures and floods (n = 5), 21,22,34,41,64 emission levels and air pollution (n = 5), 25,29,32,34,52 vegetation/deforestation (n = 3), 20,23,50 and droughts or fire (n = 3). 20,23,50 Impacts f climate change hazards on mental health and wellbeing in south America Twelve studies were included in relation to mental health and wellbeing impacts, and most of them presented findings from Brazil (n = 4) 24,66-68 and Peru (n = 3).[69][70][71] The articles primarily identified floods, droughts, and ambient temperature as climate-related hazards that affect mental health and wellbeing.The most studied mental health outcomes were common mental disorders, including trauma, depression, and anxiety, 24,70,71 and domestic violence.69,71  Five non-systematic literature reviews 24,72,73,75 described evidence regarding social and economic vulnerability stressors, climate change perceptions, adaptive capacity, and inequalities experienced by groups living in high-risk settings for climatic events.All these reviews highlighted the small number of available studies from Latin America that assessed mental health outcomes. Two cross-sectonal studies conducted in Peru 70 and Guyana, 76 one longitudinal case-control study, 69 and one case report conducted in Peru explored flood-related impacts and mental  In rural areas, there were no significant associations between heavy rainfall events and lagged diarrhoea incidence. In urban areas however, dry antecedent conditions were associated with higher incidence than wet antecedents.Also, heavy rainfall events with dry antecedent conditions were associated with 35% higher incidence compared with similar conditions without heavy rainfall events.disorders. 71 Two te-series studies explored the relationship between environmental stressors (heat, humidity, air pollutants) and hospitalisation rates and suicide cases.66,67 And there was a qualitative case study exploring family transitions and the impact of an unexpected disaster. 68 The cical appraisal concluded that all identified articles should be included in the review.At 3-and 9-months assessments, the families presented significant differences in health disorders and family violence.26.5% had some psychological disorder associated with living in shelters.Families with less than 80% safe water management and safe water storage had higher risks of acute diarrheal diseases.
Include PTSD = post traumatic stress disorder; OR = odds ratio; RR = relative risk.
Table 2: Study characteristics, key findings, and overall appraisal of articles on the main impacts of climate change hazards on mental health and wellbeing in South America.
From the evidence it is possible to identify four groups of vulnerability or susceptibility factors: i) individual factors; ii) geographical features of the natural or built environment; iii) general social determinants of health; and iv) wider policy and institutional capacities.Among individual susceptibility factors, the following were identified: lifestage or age, 64,87,100,106,113 particularly young 31,118 or old people 22,107,114,118 ; gender (being female as more susceptible) 22,64,87,100,108 ; having physical disabilities 118 or preexisting comorbidities (e.g., cardiovascular diseases, diabetes, obesity) 22,106,114 ; and being a migrant. 118he geographical features of the natural or built environment 99 were also identified as potential vulnerability factors, including living in steep slopes or mountain sides with the potential of landslides or erosion 96 ; degraded, deforested, or deserted areas 96,104,111 ; rural areas 97,100 ; and lack of vegetation cover. 99,105ore general social determinants of health 97 also were identified as potential vulnerability factors.These cover: socioeconomic 95,100,103,106,108,113,116 and sociodemographic 99,101,103,105,111 determinants, including poverty, 101,102,105 low income, 111,113,118 population health status 103,104 and distribution and population density, 98,112 and human development level 100,107 ; access to basic services, such as water 40,97,102,119 or health services; social inequalities 97,106 ; educational 64 or literacy status 102 ; and general living conditions. 102,119inally, wider policy and institutional capacities were identified as factors that could potentially increase vulnerability, including, weak maintenance/management of basic services and infrastructure 95,108 ; weak political engagement 118 ; lack of public awareness 116 ; lack of investment 116 ; weak capacity to prepare, respond, adapt, and recover 101,103,115,116,119 ; weak governance 109,110 ; lack of planning 98 ; poor risk communication. 110,117n terms of overall appraisal, most of the articles (n = 23) were suggested to be included 22,64,87,96,97,[99][100][101][102][103][104][105][106][107][108][109][110]113,[115][116][117][118][119] ; however, for seven articles 31,40,95,98,111,112,114 the recommendation was to seek further information mainly because the vulnerability factor was not clearly stated, or it was not the main variable of analysis.

Discussion
The assessment of the risk of negative outcomes due to climate hazards comprehend i) the presence and magnitude of climate hazards; ii) the level of population exposure to these climate hazards; and iii) population vulnerability which covers susceptibility and adaptive capacity.In this sense, it is desirable that adaptation and mitigation measures to protect health and wellbeing of populations consider a comprehensive evidence-based analysis of these three components of risk.
Evidence on these topics has been continuously growing in South America, allowing for a better comprehension of main climate hazards and impacts on population health.However, as it is demonstrated in this scoping review, there are still several gaps and research challenges on the intersection between climate change and population health and wellbeing, limiting further and deeper analyses of the health risks, especially analyses based on local data (see Panel 1).
These gaps and challenges do not only include the general lack of evidence and information, but also a lack www.thelancet.comVol 26 October, 2023 Gonzales, G. 36 Non-systematic review Peru Urban infestation of Chagas disease vectors were reported in Arequipa, Peru and a variable that can explain this is the rise of temperature.ENSO was associated with a proliferation of V. cholerae in epidemics due to the rise of temperature.

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Carreras, H. 89 Ecological study Córdoba, Argentina People exposed to air pollution (PM10) were significantly affected by daily temperature range, increasing the risk of hospital admissions.

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Brondízio, E. 95 Non-systematic review Amazon Basin The highest incidence of diarrheal diseases appears to occur in the rainy season and cities most affected are the ones with poor sanitation systems.

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Escobar, L. 86 Ecological study Ecuador The populations in the Andean highlands (Ecuadorian regions) would be increasingly exposed to disease vectors as the future climate changes unfold due to likely upward vector species range shifts.

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Glaser, J. 90 Non-systematic review Worldwide People exposed to warmer temperatures, coupled with decreasing precipitation, might exacerbate this kidney diseases by reducing water supply and water quality.

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Harari, R. 85 Non-systematic review Ecuador In the Ecuadorian coast, sugarcane cutters are exposed to high ambient temperatures and poor working conditions.This occupational group has a high prevalence of kidney diseases and skin cancer.

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Guo, Y. 92 Ecological study Worldwide The communities close to the equator or located in tropical or subtropical climates are projected to have a large increase relative risks of mortality associated with heatwaves, and those located in temperate regions are projected to experience a relatively small increase.

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Miranda da Costa, S. 19 Ecological study Brazil Changes in the environment might lead to an expansion of the Lutzomyia (Nyssomyia) whitmani in the northern region, especially the State of Amazonas.

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Zhao, Q. 80 Ecological study Brazil People exposed to high temperature variability have greater risk of hospitalisations, especially due to respiratory causes.

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Corrêa, M.P. 91 Ecological study South America and Antarctica Exposure of people to UV radiation differ by latitude.Seek further info Lippi, C. 87 Ecological study Ecuador The human population with the potential to experience increased exposure to mosquito presence generally increases with RCP.Ae. aegypti would expand into mountainous areas, exposing people living in transitional areas to vector-borne diseases.

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Wang, F. 94 Ecological study Worldwide People exposure to wet bulb temperature above 30-32 • C would increase significantly in the middle-and low-latitude regions.

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Zhao, Q. 77 Ecological study Brazil Exposure to ambient heat was positively associated with hospitalisation for COPD, particularly during the late hot season.The effect on heat was greater in regions like the central west and southeast and minimal in the northeast.

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Zhao, Q. 78 Ecological study Brazil Risk of hospitalization associated with heat exposure was greater for children aged 9 or younger and for people aged 80 or older than for middle-aged adults.

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Zhao, Q. 79 Ecological study Brazil Exposure to hot seasons increase the risk of hospitalisations, especially among children and adults above 60 years old.

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Zhao, Q. 81 Ecological study Brazil People exposed to heatwaves have greater risk of hospitalisations, especially due to endocrine, nutritional and metabolic diseases, skin problems, and genitourinary diseases.

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Charette, M. 88 Ecological study Peruvian Amazon Exposed children and people older than 65 years old increase the risk of dengue.The effect of temperature on dengue depended on season, with stronger effects during rainy seasons.

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Liu, Y. 96 Ecological study Worldwide Among the climate change scenarios SSP, the highest population exposure to droughts is likely under the SSP3 scenario in 2046-2065, with a 62% increase compared with that in the base period, whereas the lowest exposure was likely under the SSP1 scenario in 2016-2035, with a 30% increase compared with that in the base period.

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Alves de Oliveira, B. 82 Ecological study Brazilian Amazon Heat stress exposure due to deforestation was comparable to the effect of climate change under RCP8.5.By 2100, savannisation of the Amazon will lead to more than 11 million people being exposed to heat stress.

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Jacobson, L. 84 Ecological study Brazil People exposed to extreme cold or extreme heat changed depending on the geographical location, but both are associated with higher mortality.

Series
of diversity in terms of disciplines and geographical coverage of research in the region.This situation might affect general knowledge on the topic and subsequent public awareness, as well as the decision-making processes related to mitigation and adaptation measures at different levels (national, regional, and local), and other climate-health political integration systems.
The evidence compiled in this study represents the differential research capacities in South American countries.Most of the evidence covers Argentina, Brazil, Chile, Colombia, and Peru, leaving countries with less research capacities behind.This is relevant as several hazards and ecological changes do not respect administrative boundaries and can create important public health challenges at the regional level.Therefore, strong international collaboration is needed to efficiently face climate change and population health challenges.Additionally, climate change is a complex issue that needs a systemic approach.Most of the evidence has been generated from a few disciplines, limiting the inclusion of other non-academic actors.Interdisciplinary and transdisciplinary research on climate and health is strongly needed in SA, allowing for building stronger links between academics, policymakers, policy implementers, and affected communities from different disciplines. 120This perspective would help addressing the gap in data generation and use, as well as translating scientific evidence into practice.
There are important gaps in terms of the methodologies.Ecological studies (those that analyse data at the population level) are an important and key tool to analyse climatic and health data; however, due to the intrinsic limitations of the ecological design, the evidence might not be useful to specific local areas where the climate hazards or population health status can be Include GDP = gross domestic product.
Table 4: Study characteristics, key findings, and overall appraisal of articles on main vulnerabilities or susceptibility factors present in the South American human population groups that could increase the risk of climate change adverse impacts on health and wellbeing (n = 30).
Panel 1: Gaps and research challenges.
Although scientific evidence on these topics has increased over time in South America, several knowledge gaps and methodological issues still persist.While global information on the effects of climate change on population health is valuable, obtaining local data and knowledge is essential for developing effective adaptation policies.The impacts of climate change on health and wellbeing are mediated by local social vulnerabilities and adaptive capacities.Therefore, there is a critical need to gather local evidence on health impacts to adequately inform adaptation policies from a local perspective.Moreover, this scoping review and other complementary evidence indicate that a holistic perspective should be considered in understanding climate hazards, exposures, vulnerabilities, and health impacts, given the interwoven relationships between these elements.In order to comprehensively understand climate-sensitive health risks, a systemic approach should be taken to inform subsequent actions effectively.
different.Second, comparability of studies in SA is very limited due to the use of different databases, or metrics, or methodologies, affecting the analysis of overall impacts, exposure degree, or vulnerability factors between and within countries.This latter issue might affect the decision-making processes at national level.A final challenge considers the use and availability of good quality databases and public health indicators.Information on these is scarce and varies between countries, affecting timely and reliable data analyses.This challenge might occur due to several reasons, including the weak integration of health institutions in each country; therefore, data are not timely integrated and qualitychecked, or even it might be left incomplete temporally and spatially.It also might be happening because the digitalisation of health data is limited and has not been standardised between and within countries.
The strength of evidence presented multiple limitations.Most of the reviews were not systematic, and cited evidence of variable strength and quality, while most time series studies analysed annual or otherwise highly aggregated cases in a single or a few sites, limiting generalisability.Covariates did not include a comprehensive set of small-grid time-space climate-related factors nor it included vulnerability factors, and none assessed the intensity of disease control/prevention efforts.Reporting was also incomplete, often describing only significance and presence or absence of association without quantifying the strength of associations.Inclusion and exclusion criteria are rarely reported in sufficient detail, primarily using surveillance data "as is" without a proper understanding of its subtleties, critical in studying clinically diagnosed entities such as dengue, that often include a substantial fraction of non-dengue but "dengue-like" febrile illnesses.Also, limitations are scarcely described, as well as the implications of these limitations on the validity of the conclusions, preventing an accurate assessment of the quality of evidence.Earth sciences, public health concepts and methodology and statistical methods were not sufficiently integrated, and author's affiliations do not reflect the extensive multidisciplinary or even transdisciplinary efforts needed to produce strong regional evidence.
Many scientific gaps exist, such as the impact of deglaciation on human health, studies on nutrition and food intake, understanding the mediating role of response interventions during emergencies and many others.Similarly, an important emphasis has been placed in the impacts of climate-related factors and El Niño-Southern Oscillation, but the consequences of highly relevant human-induced hazards in SA such as deforestation, floods, droughts, fires, and air pollution remain yet a significant gap in scientific knowledge.Also, long-term or even decade-long projections do not match political cycles and decision makers may appreciate shorter time-space scales.Also, while significance of most findings is high and correlations are strong, the standard error of results is also substantial and longterm projections have wide intervals, requiring careful interpretation for decision-making processes.
There are clear impacts of climate and its extremes on human health, including morbidity and mortality; however, more refined and accurate estimates are lacking.Also, the actual attributable impact of climate change has not been sufficiently assessed, leading to the question "Do we know enough of the mechanisms and how they interact in the specific micro-scale of ecologicallydifferentiated regions?"Maybe we are making too many assumptions based on ecological (highly aggregated) studies.More cohort studies such as Mal-Ed 41 can better inform us of the mechanisms of climate-related events impact on health.
When analysing mental health impacts, this scoping review only obtained a small number of studies that complied with the stated eligibility criteria to respond to our research aim and objectives.Papers mainly reported data from Brazil, Peru, and Chile, or were nonsystematic literature reviews that lacked clear reporting of outcomes.There were no intervention studies from our search.Two papers from Peru reported intrafamilial violence amongst flood survivors and only one mentioned alcohol use in drought-affected groups.The diagnostic criteria and tools used to determine and assess the mental conditions under research were not consistent across the obtained studies.Reporting and publication bias seems likely as none reported negative mental health or wellbeing outcomes.Sample sizes also varied widely, from small qualitative studies to multicountry assessments.This study has identified disparate and minimal evidence based on climate change effects on mental health across South American countries, where underserved survivors of extreme events seem to be particularly disadvantaged.These different exposures to post-disaster stressors, in addition to the different support available across countries and the unique cultural and contextual factors, may interact in complex models, crucially impacting the individuals' and group mental health responses and conditions.There is a concerning lack of formal assessments addressing these impacts with cultural and gender sensitivity, and community-based in mind.Furthermore, the methods and results of many included studies were frequently poorly reported, so methodological biases cannot be ruled out.This evidence paucity should be a call for action to address mental health and local factors with a transdisciplinary lens at all levels to translate them into policy and community engagement.
In terms of the analysis of exposure to climate hazards, evidence is scarce and limited in understanding the concept of population exposure that is generally mixed with vulnerability factors.This limited evidence might affect the study and identification of people highly exposed to hazards, which in turn limits the adaptation measures to reduce vulnerability.Therefore, it is important to spatially and temporally analyse to what extent population is exposed to hazards, identifying areas prone to be affected by the hazard as well as areas prone to disasters, where the link with social vulnerabilities is important. 121dditionally, most of the evidence analyses exposure to heat extremes and its consequences; however, the exposure to cold extremes is less studied and understood, leaving an important gap in terms of temperature exposure and the associated changes.
Regarding the identification of vulnerability or susceptibility factors, it is important to highlight that the scientific evidence identifies different factors at different levels, which is key to the correct identification of most vulnerable population and subsequent targeted actions.Individual susceptibility factors, such as age and comorbidities, and wider social determinants of health, such as socioeconomic status, have been identified in South American populations.Unfortunately, as most of these articles have taken an ecological approach, it might be difficult to assign specific risks to different populations.Public health practitioners or epidemiologists can take this information as an overall perspective and then analyse their own situations at local levels, but that would require specialised technical skills.Additionally, geographical and wider policy and political determinants are also identified, which are undoubtedly associated with the vulnerability of populations to climate hazards.In this case, these determinants are more associated with the capacities of institutions to respond, adapt, and recover from shocks or stresses, as well as the financial support and political will to progress in adaptation and mitigation measures.Unfortunately, evidence in SA has not integrated a general or standardised framework to understand and analyse vulnerability to climate hazards, leading to a wide range of definitions and approaches to susceptibility and adaptive capacities.There is a need for establishing a clear and useful framework that could guide the identification of vulnerable populations and subsequent policy measures.It is desirable that this framework would include a dynamic social approach to vulnerability given the multidimensional nature of population vulnerability to climate change. 122ased on the current published evidence, this is one of the first studies to apply a systematic approach to revise the scientific evidence on the three components of health risks associated with climate hazards.It marks a great precedent in the field of climate change and health and helps guides research to strengthen the practice and research on the field.Nonetheless, this study has some limitations.First, it did not include searches using Spanish and Portuguese key terms, which may have limited the number of articles and introduced some language biases.Second, the search was restricted to impacts, exposures, and vulnerabilities to climate change, excluding evidence related to impacts of climate, weather, or environmental hazards.This may have excluded several articles that only consider other environmental perspectives or frameworks.Additionally, as the search was restricted to climate and health intersection, other areas involving health-determining sectors may have been excluded as well.
In order to continue working on this area, the Working Group on Health Hazards, Exposures, and Impacts of the LCSA aims to track the health hazards, impacts, and exposures to climate hazards by quantifying and analysing sound and scientific-based indicators considering a regional perspective.

IncludePalmeiro-
Silva, Y. 60 Non-systematic review Chile The number of heatwave exposures for the elderly has increased over time.Wildfire exposure has almost tripled when comparing the periods 2011-2004 and 2015-2018.Seek further info RCP = representative concentration pathway; PM = particulate matter; SSP = shared socioeconomic pathway; ENSO = El Niño-Southern Oscillation; COPD = chronic obstructive pulmonary disease.

southwards the habitat of Anopheles darlingi, it's most efficient vector, potentially doubling the number of people at risk of year-round malaria transmission from 25 to 50 million between 2020 and 2080. Additionally, the high fraction of urban populations coupled with rising temperatures could increase the potential of dengue transmission intensity by a factor of 2-5 and expand southwards, in part due to predominantly urban Aedes mosquitos.
deforested rural areas present an increased risk for leptospirosis via floods, dengue, Chikungunya and Zika, hantavirus outbreaks, and yellow fever.Increased incidence of urban arboviruses is associated with areas with more frequent rainfall and severe droughts, since both factors can favour breeding sites for the Aedes spp.and Culex spp vectors.
into closer proximity of anopheline vectors for prolonged periods, and 3) flood response efforts took away energy from malaria prevention efforts.Finally, the 2010 drought and increased temperatures could have accelerated Plasmodium's development in Anopheles mosquitoes.Include Sena, A. 23 2014 Non-systematic review Brazil In Brazil, the semiarid northeast is a historically and permanently dry area, where extreme drought occurs periodically affecting a large population and causing population displacement and economic losses.The northeast also has some of the worst health and wellbeing indicators in Brazil.Although social and economic vulnerabilities have been partially reduced, climate change will probably impact severely this region.Include Smith, L. 17 2014 Ecological study, time series Brazil A 1.3%-181% increase in hospitalisations for respiratory diseases in children under-five was observed in the 77 (31.3%) municipalities highly exposed to drought, compared to their 10-year mean.A 1.2%-267% increase was observed in 197 (43.0%) municipalities affected by the 2010 drought.Aerosol was the main factor associated with hospitalisations in drought-affected municipalities during 2005, and human development conditions may have mitigated the impacts in 2010 cardiovascular and respiratory mortality, respectively.Risks were higher for females and people with no education about heat effects, and males for cold effects.Older persons and widows had higher mortality risks for heat and cold.Mortality during heat waves was higher than on non-heat wave days for total, cardiovascular, and respiratory mortality.Both heat and cold effects remained after adjusting for pollution markers (PM10 and ozone) Include (Table 1 continues on next page) 19 2018 Ecological study, time series Brazil Niche modelling identified that the preferential habitat of Lu. whitmani includes annual precipitation between 1000 and 1600 mm, intermediate vegetation density, 15-21 • C average temperature of the coldest quarter, and 19-24 • C annual average temperature.American cutaneous leishmaniasis is associated to areas of intermediate vegetation, rainfall of 800-1200 mm, coldest quarter mean temperature >16 • C and annual mean temperature <23 • C. Include Leal, W. 15 2018 Non-systematic review Brazil Weather pattern shifts can also favour new vector niches.Such changes could have influenced the recent Zika and Chikungunya emergencies in Brazil, amplified by one of the strongest El Nino event in recent years.There is limited local evidence to understand these patterns and use and support disease control.Seek more info Tapia-Garay, V. 2018 Ecological study Chile The maximum temperature in the warmest month and precipitations in the driest month correlated importantly with the distribution of Chagas' disease and T. infestans in Chile.Annual precipitation, temperature seasonality and average temperature additionally contributed to Chagas' disease distribution.Include Laneri, K. 54 2019 Ecological study, time series Argentina There were lagged, non-linear correlations between malaria cases and maximum and minimum temperature and humidity.Seek more info Lopes de Moraes, S. 24 2019 Ecological study, time series Brazil Childhood hospitalisations for respiratory diseases were statistically significantly higher for mean air temperature (17.5-21 • C), relative air humidity (84%-98% for females only), precipitation (0-2.3 mm for total and both sexes and >120 mm for females) and PM10 (>35 μg/m 3 for total and females).(Mar01-May31) when evacuees returned to their communities, but rains and flooding continued, there was sharply increased risk of rotavirus and sapovirus, and increased Shigella spp.transmission and Campylobacter spp.Include da Silva Neto, A. 2020 Ecological study, time series Brazil The annual incidence of visceral leishmaniasis in Mato Grosso do Sul from 2002 to 2015 correlated negatively with both the mean 3.4 El Niño index variation and soil moisture.Include (Table 1 continues on next page) Series www.thelancet.comVol 26 October, 2023

Table 1 :
• C increase in temperature is associated with 3.8% more childhood diarrhoea clinic visits three weeks later.Adjusting for temperature, there was a higher incidence rate of childhood diarrhoea clinic visits during moderate/strong El Niño events and during the dry season.There was no evidence that access to piped water mitigated the effects of temperature on diarrhoea incidence.higher in municipalities with floods in all five population-size municipalities and also in municipalities experiencing more outbreaks.Regression trees showed that the fraction of households with pit sewage disposal, >3 flood events, and cities in the second level of population size had different leptospirosis incidence.Study characteristics, key findings, and overall appraisal of articles on the main impacts of climate change hazards on physical health and wellbeing in South America.Losses associated with disasters influenced social lives, daily routines and the preservation of cultural values.The interviewed families made their interpretations based on their life experiences and by comparing and evaluating the event's impact in relation to other affected families.Their perception of the event's magnitude tended to focus on damage and loss, reducing their understanding of the context of the event to a micro level, without any association with prior knowledge of the risks to which they were exposed.Their narratives denoted the family vulnerability and resilience in relation to the unexpected disaster transition, and the postdisaster recovery of the family in its social, economic, and environmental dimensions.
Series www.thelancet.comVol 26 October, 2023 Case studies conducted in Chile illustrate the findings.Some relate to vulnerability, and stress due to the perceived effects of climate change and there is a need to dialogue between the holders of traditional knowledges and scientists, to achieve a joint work with the communities on mitigation and adaptation strategies.

Table 3 :
Study characteristics, key findings, and overall appraisal of articles on to what extent human populations in South America are exposed to the hazards of climate change.